Subtypes of Influenza A viruses (IAV) cause the “flu” in birds and some mammals, including humans. Influenza hemagglutinin (HA) is a glycoprotein on the surface of these viruses that binds to the membranes of host cells to enable viral entry, and thus plays an important role in infection.

Scientists have extensively studied this protein’s structure and synthesis. However, little is known about how HA moves through the network of organelles inside the host cell and reaches the membrane. Live imaging of HA in IAV-infected cells can enable such studies. Researchers in different countries, including Shashank Tripathi at the Centre for Infectious Diseases Research, have collaborated to develop a new method to enable the visualisation of HA in infected cells.

This technique involves engineering a recombinant virus which has a tetra cysteine tag that emits fluorescence in the presence of biarsenic dyes, and can be rapidly detected. This method can be used to study IAV infection even after viral fusion with the host membrane, and could aid the discovery of antiviral drugs.